Marking circuit-arrangement for positioning a final selector switch



Dec. 10, 1957 B. H. GEI-:Ls ET AL 2,816,171

MARKING CIRCUIT-ARRANGEMENT FOR POSITIONING A FINAL SELECTOR SWITCH Filed July 5, 1952 y 2 Sheets-Sheet 1 Dec. l0, 1957 B. H. GEELs ETAI- MARKING CIRCUIT-ARRANGEMENT FOR PosITIoNING A FINAL SELECTOR SWITCH 2 Sheets-Sheet 2 Filed July 5, 1952 nitecl States Patent i MARKING- cIRcUIT-ARRANGEMENT Fou Pos1- TroNnao A FiNAr sumaron sWrrcH Bernardu's.I-Iendrikus Geels, .lan Louis de Kroes, and,

telephone systems, for the numerical positioning oa vnal selector switch, a numberof outlets from 'which is associated with a' com-mon number` (P. B. Xgroup). b l

Ithas been suggested to provide a circuit-arrangement in which the numerical positioning of selectorfswitches is effected byte'sting under the control of a controldevice. In this case, selector switch outlet test contacts wiped by a rst testwiper ofthe selector switch, are connected to marking conductors. Test contacts of outlets which correspond to the same number are connected to the'same markingf conductor. After reception of dialling pulses, the control devi-ce marks the test contact of the outlet or outlets corresponding to the desired number via the marking conductor concerned, for example, by connecting thisconductr ytoa terminal `of a voltage source.,` As

soon asa selector switch reaches an outlet thus marked a test circuit is established across the test wiper, thetest v contact of the selector switch and themarking conductor y and in this circuit a testrelay is energised, thus stopping the movement ofthe selector switch. This is followedby a test via a further test wiper of the selector switch to indoutwhether the outlet isrfree `or busy.

Such av circuit-arrangement has several disa'dvfantages".

Thal-outlets of a group with which 'a commonnumberis associated must be characterized as` such outletsjbecause@ if the selector .switchhas stopped on a` busy outlet of such a 4group it should be possible for the test to be repeated with other outlets of the group.` However, such 'markingl requires a supplementary wiper on the selector `switch orL elsejja4 marginal voltage test is required to be eliected.`

Further,lif an operator Wishes to connect along distance call fand all the outlets for the group are busy itmust be jpossible to effect through-clearing of a busy outlet. In theknown circuit-arrangement this is possible only with the last outlet of the group because lirst all the'outlets must be tested before it is apparent that the outlets '1`l1eV object of the invention is to provide an improved marking circuit-arrangement for positioninga nal selector switch. i

According to the invention, a marking circuit-arrangement for use inan automatic signalling system, more particularly Ain an automatic telephone system, for the numericalpositioning of a nal selector switch, in which test contacts Vof outlets of the selector switch are connected to marking conductors and outlets corresponding to the same number areassociated with the same marking conductor, control means being provided for the purpose of marking the test contact of a wanted outlet via a marking conductor in accordance with dialling signals rel ceived, causing the marked outlet to be found by the selector switch and testing whether the outlet found is busy, is characterized in that the test contacts of a group of outlets corresponding to the same number are con- ICC nected to the marking conductor associated with this group via contacts of relays associated with the outlet (not permanently as in known circuit arrangements) such that if an outlet of the group is free the test contact of at least one free outlet and of none of the busy outlets is connected to the marking conductor and if all the out lets are busy the test contact of at least one of the busy outlets is connected to the marking conductor.

When a freev group outlet is available the selector switch passesgany busy outlet(s) of the P. B; X group and can `stoponly on a free outlet. However, if all the outlets 'c of the group are busy, one or more busy outlets on which Y the selector switch can stop for connecting a call `are indicated. There is consequently no necessity for marking P. B.`y X-group outlets as such, and through-clearing is Ypossible on any group outlet intended for this purpose or 4'on allthe outlets of thegroup.

The invention vwill now be described with reference to the accompanying diagrammatic drawing, given by way of example, in which twoembodiments of the invention are .shown.

Fig. 1 illustrates the circuit diagram of a relevant portionjofan automatic telephone system in accordance with this invention, and b Fig. `2 illustrates a modification of the marking circuit ,shown ,in Fig.`1 in accordance with this invention.

Figgl shows in a simplified form a subscribers station AB, Which is one of a group with which a common group `number is associated, a line circuit LC associated with station AB, part of line circuits LC and LC associated with other stations `of the group and a final selector switch EK the positioning of which can be controlled by a control device BI common vto a number of nal selector switches. In addition, OZ and GK designate a call finder and a group selector switch, respectively.

A The line` circuit LC includes a line relay L andl a slowto-release cut-off relay S having two windings S1 and S2. The relaycombination may assumerfour different conditions.v inthe normal condition both relays-L and S are defenerg'ised. `When the subscriber at station AB lifts the receiver to initiate a call, the line circuit assumes the calling condition in which the line relay L is energised in a circuit fromearth via break contact s1 of relay S,`

intelligence conductor bl, the line loop via the subscribers station AB, intelligence conductor al, break contact.s3 :of relay S and winding of relay L to the negative terminal BA of a battery (not shown) the positive terminal of which is connected Yto earth. In this condition, a starting circuit is closed` via break contact s2 of relay S and make contact l2 of relay L with the result that a call nder OZ finds, in known manner, the outlet for the calling line, saidoutlet being indicated as calling due to the closure 4of contact I4 of relay L which connects voltage from BA to the wiper c3 of the called finder OZ. After the line is found, the wiper c3 of the call nder is connected to earth potential by means not shown, so that the relay S is energised via contact Z4, winding S1 and the win-dingof relay L, sothat the line circuit LC is changed to its third condition (intelligence condition), the two relays L and Sare energised and the line is marked busy due to `the conductor cl being connected to earth potential.

If the required connection is not established, for example, because the called station is busy, the connection of wiper c3 to earth in-the call finder OZ is interrupted v n vand relay L is thus de-energised because contact S3 has by now broken the energizing circuit from L to conductor al. Smce, however, relay S is a slow-to-release relay, it

is held energised` inl a circuit from earth via break contact l1 of relay L, make contact s, of relay S, intelligence conductor bl, the line loop via the subscribers station AB,

Patented Dec. 10, 1957` t0 .busy-i911@ genereer (lletlwwnh.avclftheypltageat; f

BA1. The. lneiicvitl ,ttes @rubies tstoiitth. Candia. tion @icy-tone holding. candidati),innltichslax S @11,1 y,-

iS assigned andthelivtyanesenrator supplies abusif.. mato the .Subscribers stati@ .A1B views-Sai holding circuitl of relay S. vIf the ysubscribfzrtat stationB then .s

replaces the recetyer, relay isreleasedby reason they i line` leop'through ABl4 b'erir'igl broken, K txhe line circuit LC thus returning to itsnoriynal condition,

, .i-wntiuifh If'the subscriberys statylonns connectiedhvia final selectorl earthllpotcntialsothat 'relay' Sy (via, S12 an, ,relay l L a@ enefgiseaant the lfn ein# Lc..'is.tins.hias;ntfd. Coffdtiee- .At the .eetl @i thacallatheear-th .anatema to w'ipencz ispinterructed, with, the rcsultthatl thenline circuit assumes its fourth I condition as; describel A.abcnl'c f and th`e'sub`scriber at station 'ABfreceiveea'busy'tcngg'prof1 vided that the subscriber has notlpreviously replaced the receiver;A Y .1. .i l' i The numerical positioningof Ithel `final selectotsfvfv'i` is effected by'testing under th'e'co'ntrol ofthe control device Bl. yThe control devicecomprisesl a marking Iswitch having some hundred outlet'contacts corresponding@ 'thel various combinations ot the last ltw'o digits'cf thesub` scribersnumbers and these outletI contacts 'areea'heh con, nected via' oneofvthey'rnarkingcondnetors'MN ofthe test contacts wiped by wiper d of'hfe1 inalselectorsv'vitch, such forl example, as u1, u'2,l`u3ar`1d`u4=, an'tll are associated witlroutlets tor'the final se1ec'tor1fEK corresponding numerically tojthey outletcon'tacts of 4the ,test switch MS.

T h'lefoutlet contacts 141,142, u3'are associated with outlets ofna group of lines with whlivcbafcomrr'to'n Iniimber is associated. The test 1contatcts ar'connected', via contacts` of the'lline, and `cutolf relay ,ofthelinegroug to a come. mon marking conductqrfMGfwhichs "connected totthat outlet contactof theswit'chv MSwhich corresponds to the` grolipn'unikger.l It allthellines'of thegrouparevfree, test` Contact u1 isconnectedjto the markingi'condctor yMG via, the series "combination of ,break 'contacts ll1", and `s1 of the line relay (not showln) atid thccut-oi' relay,` (not,` shown) associated with the linecircuit LQ. If theline circuit `LAC is busy and vtheflitne circuitLC, is'free, testcon-` tact n is connected to conductor MG, via break contact l.1` of relay l., break 'contact .hof -relay'S 'a`r"1df rnakey contact If both' circuits L C'andy LC arek busy, test contact 1,43 isf connected to conductor MG via breaky contactsl4f and s1".. of the.:line'relay@(notv'shoifvn) tand ,the cut-off relayftnot shown), respectively of line'circuitfLQ'f, 'make,'c0ntac't s4 of wrelays and4 make contact s1" of the line circuitlLCzll Theireis conseil-uentlyv always atest contact of 'a freeot; let aiiailable'and no test contacts of busy outlets are 'con-1', nec'ted to `1conduitor M G solofngxas Athere is still 1an" outlet free'uin the" groupi t Thus, 'the relay'chain circuit ot the. makc'aodbreakicontact's Si', S4 'and A34." always indicates iIiA a giieno'rder a tree on.tl et.,'vi f oneis available. However, if all''thebu'tl'et'sl for, thefgroup are busy,`.the test contacts" u1 and u'zare connected to `conductor MG via the make` contacts 1,1", s4", s4jand ls'i'and l4,s.1", s4 and. s4', lrespccf tively. Thus both when all the lines are busyand when free lines are available in the group, there is alwaysat least one of the marking contacts 'of the group, which is connected to theconductor MG so that it is always possi,- ble for lthe nal selector switches to find a marked outlet of the group, .this ,outletbeing in the rst case a busy outlet and in the second case a free outlet. l

The circuit arrangement operates ays'tollows. t,

On'the linal selector switchEK and the controldcvice 4 BI being engagedv by the gronpI- selector GK, conductor cg is cnn'ecte'd'to earth` by means not shown, with the' re:

sult that' tlie connecting 'relay "VM and the marking' relay H are energised from the voltage BA `via wiper"c1 and 'teelt v .ceatatpt .gl'taupiselectot bteaksomact p1, ot relai/,1%.

winding of relay winding H1 and break contact h1 of relay H. As a result of break contact h1 being opened, relay H connects its high-'ohrnic winding H2 in series with the low-ohmic winding H1,lwi,t htlhe result that inal selectin .Switch .EK and. the @11H91 device B1, are, .marked engagedl The dialling ,pulses are, fedwas earthin'gj pulses" via conductor ag, wiper a1 and test contact of group selector G'K, intelligence conductor Lak, make contact `m3 of relay M and break contact y. of relay Y (not shown); to a pulse-receiving relay O ofthe controldevice and under the control of this relay the test switch MS is posi# tioned in a known manner not further described herein, in accordancerwith ,the dialling pulsesl received. The marking switch MS is shown in Fig. l as a switch, having a wiperwhich contacts with a number ofA outlet 'contact'sf however, it is obviousthat as an alternative use may be made ot Geiger-Mller tube circuits comprising relays.

Assuming A, that the number 1 pt* the lineY group ,has b een selected, the wiper of switch MS is t h en positioned to connectto the'outlet contact connected to conductor MGM l After-the dialling signals are,received,relay Y,A is cnergised, i by means nowhown S9 that the Iman/magnet DM Qf.;

the tivnal selector vEl( isI energised. via make contact Ih2 ot relay IH, bmakc, contact I y2 of. ,relay Y, t vbreak contactnt1 of the numerical test. relay NT and make contact mgofg relay M and the Selscfar. Switch is Startediwlhilst a numeri: calftes'tcircuit lisuprepared from earth, via make contacts hz .and `yan/indias 0fy Islay NT,.ma1, entaCtma.9t relay M, wiper d2] and the test contact of a desiredout?1 let for the Vfinal selector EVK, the connectionthereof'to c0111.#A ductorMG viacontacts of line' and cut-off relays, .conductor MG, outlet contact andA wiper of switch MS t0 battery.' ,I y l Assume now'th'at line circutLQfis busyand the line to station ABQis free. In thiscase, the testr'elay 4NT will b e energised inv thesaid test circuit as soon as the,

wiper d2' ofl'inal selector EK reaehes thetest contact.,

u2, which isv connected to ybattery BA'via'breakcontactsA l1 and s4, 'makev contact s4', and the outlet contact and. wiperofswitch MS. Then'zbi'eak contact *.nt'1of; relay. NT breaksthe energizing circuit` otrotary magnet Dill/:I so that the selector stop, and closes a second test circuitl for'testing 'whether thef'outlet is busy or'fr'ee. Thisft t,.

is necessary, since, vas mentioned hereinbefore the'selectoi' can also be st c'lip'ped4 on busy'outlet,l if. all the ontletsfor,v thev groupl ,a'1"fl`:,'l:yu`syI acndlnd diiei'ence 'is' cother?vise;'miaoe between individal'subsc'ribers linesfand lines ass'octat'edg,

from earth `v1a makelconta'ct's h2, vyzfar'td' m1, 'Windigloff the relay BT, maketcontacturyof relay M, rwiper ',c11` Iandi,

test contact fotnal selector VEK, .conductorfcL ,winding S1 of 'relay Sand 'relay'Lto batteryBA. Since the, ,outletl Y make contact 'PQHWlh'the 'result'that 'the'outlet isl'marke'd';

busy and, vi'its lmakc'contact-s pjland'fp, connects intelligence conductors ak and bk to the-wipe'rs 0.2 and' b2 of the' finalselect'or switch. In addition,via xitsniake contact"p1 andits'second winding'Pg 'relay l closes al hoidin'g'circitfp'r itself.

-relays BT, NT atidfY' k(,not'shovvn)' are de-energised the switch MS is restored'to its nori'naiposition by means not shpwn.

In this 'case'the'test contacts ry1fancluz'xre connected toy conductor MG via makecontacts' 11'; n1", 's1 and s4" and D Aueu .tok contact p1 being opened, the yrela'ys'M'arid Hare de-energi'sedtso that" y I4, s4", s4 and s4', respectively. On any of these outlets, for example, that of the subscriber line AB, being reached, relay NT will be energised in a circuit from earth via make contacts h2 and ya, winding of relay NT, make contact m6, wiper d2 and test contact u2 of final selector switch EK, make contact I4, make contact s4", s., and s4', conductor MG, outlet contact and wiper of switch MS, to battery BA so that, in the manner described above, the selector switch ystops and the second test circuit is connected via make contact ntl. Since in this case the outlet is engaged and the test contact u2 of nal switch EK, which contact -co-operates with Wiper c2, is consequently earthed, relay BT is not energised. Conductor ag is then connected to earth via wiper a1 and contact of the selector GK, intelligence conductor ak, make contact m3 of relay M, make contact y1 of relay Y, make contact nts of relay NT and break contact bt of relay BT as a sign that the outlet is busy. In this case, under the control of means in the connecting circuit, the connection will be broken, so that the earth connection of conductor cg is removed, the relays M and H are de-energised and the circuit re-assumes its normal condition. However, if the call is made by an operator, who wants, for example, to offer a call, she may effect through-clearing of the busy line. For this purpose, conductor bg of the selector switch GK is earthed so that relay P is energised via the wiper b1 of the switch GK, make contact m2, make contact m1 and winding P1. Relay P makes direct connection to the loop wires via contacts p2 and p3 and opens the energising circuit of the relays M and H, with the result that control device BI re-assumes its normal condition.

Fig. 2 shows a modification of the marking circuit arranged so that if some of the lines `are free, test contacts of all the free lines are connected to conductor MG via the series combination of a break contact I4', Z4, L, of the line relay associated with the line and a break contact s4', s4, s4" of the cut-or relay. This consequently enables the selector switch to stop on any free outlet. If all the lines are busy, the test contacts of some or of all of the lines of the group, for example, the test contact u2, are connected to conductor MG via make contact I4 of the associated line relay and in addition via the series combination of make contacts S5", S5 and S5 of the cutoff relay of all the lines of the group.

In the circuit-arrangements shown in Figs. 1 and 2, the contacts of the free outlets are connected to the marking conductor via break contacts each of which is open when the associated relay of the line relay and cut-ott relays is energised with the interposition if desired, of break similar contacts of cut-off relays of other lines. Thus the test contacts of calling lines or other lines the line circuit of which-is in the fourth condition, in which consequently in the iirst case only the line relay and in the second case only the cut-ot relay is energised, are not connected to the marking conductor and hence cannot be engaged by the nal selector switch. As an alternative the circuit may be arranged so that test contacts of free outlets are connected to the marking conductor only via -a break contact which is open when the line relay is energised or only via a break contact which is open when the cut-oft relay is energised, whereas on all the outlets being engaged the test contacts of some or of all of the lines of the group can be connected to the marking conductor via a circuit which includes a make contact which is closed when the associated line relay or the cut-off relay is energised and make contacts each of which is closed when the associated relay of the line or cut-olf relays of lall the line-s of the group is energised. Thus, for example, in the circuit shown in Fig. 2 direct connection may be made between the break contacts I4', I4, l, or alternatively between the break contacts s4, s4 and s4', or in other words these contacts are omitted. ln the former case, the lines can be engaged by the nal selector switch EK also in the calling condition and in the second case also in the fourth condition.

What we claim is:

l. In an automatic telephone system provided with a nal selector switch having outlets including test contacts and having a wiper adapted to selectively engage said test contacts; a marking circuit for the numerical positioning of the wiper of said selector switch comprising marking conductors, control means for electrically marking the test contact of a wanted outlet via a marking conductor in accordance with incoming dialling signals, means to cause the marked contact to be found by the wiper of said selector switch and to test whether the found outlet is busy, and a system including relays provided with contacts normally connecting the test contacts of a group of outlets corresponding to the same directory number to a marking conductor associated with said group, said relays having additional contacts adapted to connect the test contact of at least one free outlet and none of the busy outlets to said marking conductor if an outlet of the group is free, and means responsive if all the outlets are busy to cause said relays to connect the test contact of at least one of the busy outlets of the group to the marking conductor.

2. A marking circuit as set forth in claim 1 wherein the test contacts of the group of outlets corresponding to the same directoil number are connected to the corresponding marking conductor via a first circuit of the relay system which includes a contact which is open when a relay included in said lirst circuit is operated, said relay being operated only when said rst circuit is in a rst condition, and wherein the test contact of at least one of the outlets of the group is also connected to a marking conductor via a second circuit of said relay system, said second circuit including the series combination of make contacts each of which is closed when each relay corresponding to the rst circuit relay of each outlet of the group is operated, said relays being operated only when said second circuit is in said first condition.

3. A marking circuit as set forth in claim 2 wherein said first circuit includes the series combination of two open-on-operation contacts of relays included therein, one of said open-on-operation relays being operated in a second condition and in a third condition of said rst circuit and the other relay being operated in said third condition and in a fourth condition.

4. A marking circuit as set forth in claim 3 wherein at least one of said first circuits further includes closedon-operation contacts of relays connected in the circuits of other outlets of the groups.

References Cited in the le of this patent UNITED STATES PATENTS 1,799,175 Merk Apr. 7, 1931 1,840,950 Hatton Jan. 12, 1932 2,583,014 Pouliart Ian. 22, 1952 2,593,418 den Hertog Apr. 22, 1952 2,602,122 Lesigne July 1, 1952 2,692,617 Mange Oct. 26, 1954 

